<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <meta http-equiv="X-UA-Compatible" content="ie=edge">
    <title>Document</title>
    <style>
    
    img{
        width:300px;
    }
    </style>
</head>
<body>
    <img src="images/placeholder.png" alt="" id="show">
    <button id="modern">现代</button><button id="old">古典</button>
    <script>
    var img=document.getElementById("show");
    var modern=document.getElementById("modern");
    var old=document.getElementById("old");
    modern.onclick=function(){
        img.src="images/现代.png";
    }
    old.onclick=function(){
        img.src="images/古典.png";
    }
    </script>
</body>
</html>